A History of Fish Glue as an Artist's Material:
Applications in Paper and Parchment Artifacts

Tatyana Petukhova

Received for publication Fall 2000.

Abstract

This article presents a brief historical overview of fish glue as
an artist's material applied to paper and parchment artifacts.
Artists and craftsmen have appropriated this natural glue since
antiquity. Artists have used this material in the preparation of
binding media and adhesives, the source for which was a commonly
available fish protein. Scientific publications and practical recipe
books refer to the use of animal and fish glues in the making and
restoring of objects, icons, paintings, illuminated parchment
manuscripts, and other artifacts.

In this article the author describes only applications of
fish glue compiled from the records where it was mentioned as
a separate entity.

Early References to Fish Glue

Fig. 1. Sturgeon air bladder membrane for making
isinglass.

Glue can be extracted from fish by heating the skin or bones in
water. The purest form of fish glue, made from the membrane of the
air bladder (swim bladder) of certain species of fish such as the
sturgeon, is also called isinglass (fig. 1).
Isinglass can be produced from various species of fish using diverse
manufacturing processes. Depending on the manufacture, the purity of
isinglass can vary. Historic sources do not always specify which
part of the fish was used to make the glue.

There is no record telling us exactly when and where the first
animal or fish glue adhesives were used. However, it is known that
at least 3500 years ago these adhesives were used in Egypt. Even
though Egyptian records do not describe in detail the adhesive
preparation process, they do tell us that it was made by being
melted over fire and then applied with a brush (Darrow 1930, 9).

From the first-century Roman scholar Plinius we learn that two
kinds of glue were used in antiquity: animal glue (taurokolla
in Greek, gluten taurinum in Latin), made from the skins of
bulls, and fish glue (ichtyokolla) made from some parts of
fishes. In references to the glue used by ancient craftsmen, both
terms xylokolla (in Greek) and gluten fabrile (in
Latin) are cited; however, it is not clear to which kind of glue
these terms applied (Gug 1975, 37).

In an eighth-century European manuscript from the Cathedral of
Lucca, fish glue is recorded as a material for painting. A. P.
Laurie translated this manuscript into English in 1926; it tells
that the pigments in fresco paintings were applied to wet plaster
without mixing them with a binding medium, using only water. For
panel paintings wax was mixed with the pigments, and for
illuminating parchment manuscripts fish skin glue was used (Laurie
1926, 107).

In the Middle Ages in a twelfth-century treatise on methods and
recipes for painting and illuminating by the German Benedictine monk
Theophilus, fish glue appears once again. In his Schedula
Diversarum Artium (Ch. XXX) he gives directions for grinding
gold and then mixing it with fish glue for use in gilding of
illuminated manuscripts. He continues, (Ch. XXXIII):

... on every sort of glue for pictures of gold, if you have not a
bladder cut up thick parchment or vellum. ... Prepare also the skin
of an eel. ... Prepare thus also the bones of the head of the
wolf-fish, washed and dried, carefully washed in warm water three
times. To which ever of these you have prepared, add a third part of
very transparent gum, simmer it a little, and you can keep it as
long as you wish. (Laurie 1926, 167)

In around 1390 Cennino Cennini (an Italian artist trained by
Agnolo Gaddi), the author of the Craftsman's Handbook (Il
Libro dell'Arte), mentions earlier applications of fish glue
in restoration: "This glue is made from various kinds of fish . . .
it is good and excellent for mending lutes and other fine paper,
wooden or bone objects" (Cennini [ca. 1390] 1960, 66-67).

Historical Uses of Fish Glue

As we can see from ancient and medieval records, fish glue was
both a common and important adhesive for many special applications;
adapted by artists, it was used from the time of ancient Egypt to
twentieth-century France, in painting media, coatings and grounds,
in the gilding of illuminated manuscripts, and in pastel fixatives.

Illuminated Parchment Manuscripts: Sizing, Gilding, and
Repair

In medieval Europe, parchment was the main material for writing.
It was usually made from sheep or calf skin, but occasionally from
the skins of such other animals as goat, antelope, and gazelle.
Preparation of the parchment was a time-consuming procedure
requiring special skills. One of the many steps in the process was
sizing of the parchment, which enhanced its strength and prevented
the writing medium from penetrating too deeply, allowing the
parchment to be reused. When the parchment was to be used over
again, the old ink or gouache-like medium was removed from the
surface by rubbing pumice over it; the area was then softened so it
could absorb new writing.

Two types of size application, coating and impregnation, were
employed. The sizing solution was generally produced from scraps of
parchment or trimmings of the whole skin of an animal. Small pieces
were then soaked and boiled in fresh water. Fish glue was also used
to size parchment. According to D. V. Thompson, this size was
prepared from the sounds (air bladders) of stockfish and sturgeon in
a manner similar to that used for parchment preparation (Thompson
[1936] 1956, 59).

Thompson also mentions fish glue in the context of stabilization
(mending) of damaged sheets of parchment, ground preparation for
laying gold or pigments, and as a binding medium (fig. 2). The purpose of the binder was to hold
particles of pigments together allowing for the paint to be firmly
attached to the surface of the parchment. The area on which the gold
leaf would be laid was coated first with a solution of fish glue.
The property of fish glue to adhere well to the porous parchment
support made it a useful material for illumination of manuscripts
with gold leaf and painting.

Oriental Painting and Calligraphy on Paper: Binding Medium

In China various kinds of animal glues were implemented as
binders in paint media during the T'ang dynasty (618-906 a.d.).
According to records of this period, for example, one of the
essential components of lampblack ink was proteinaceous glue (Sze
1956, 67-68). One of the high quality inks used at that time was
made from donkey hides and then mixed with carbon pigment. It is the
glossy characteristics of that particular ink that make it easily
distinguishable by specialists today. The particular kinds of animal
glue that were used during the manufacturing process have, over
thousands of years, preserved the distinct features of this finest
quality ink.

The Chinese of the T'ang Dynasty manufactured many grades of
animal glue. Glues were produced from horns and hides of deer, hides
of cow, and skins of fish. Chinese documents of the ninth century
record the employment of hide and fish glue in paint media (Winter
[1936] 1956, 117). Fish glue from Wu (Kiangsu province) was
mentioned, among other paint binders, such as ox glue from Santung
and a stag-horn glue from Yun (Yannan province) by the T'ang critic,
Chang Yen-yuan (Siren 1936, 232). These glues bind particles of
pigments together, forming a film over the ink surface as the ink
dries. This coating functions as an organic barrier, which protects
ink from the hazardous effects of the environment. The glue also
provides an adhesion between particles of pigments and the support.
Chinese traditional supports on which ink was applied were, and
still are, made from porous materials such as paper and silk. These
supports allow the binding medium mixed with pigment to penetrate
into the fibers and create a strong bond with it that is beneficial
for the stability of an ink medium.

Gouache on Paper and Board: Glazing and Coating

In the nineteenth century some artists experimented with
non-traditional techniques. Some of these innovations were taken
seriously by other artists of the time, but they often failed. The
gouache paintings by M. Pierran, for example, which were coated
heavily with glue in order to obtain a special effect, were
exhibited in the 1834 Salon. These gouaches with their glossy
surfaces resembled oil paintings. The technique involves application
of the mixture of gouache with a large amount of gum and fish glue.
These paintings over time have developed delamination and cracking
(Bazzi 1960, 109).

Another method of painting with watercolor on specially prepared
Bristol board was developed by C. J. Robertson, for which he
received the Medal of Isis from the Society for Encouragement of the
Arts, London. The process, from the backing of a Bristol board to
the coating, was elaborate. When the picture was completed it was
"varnished" with a solution of fish glue and then with a good
quality picture varnish. "The advantages of the method are that the
color, which stays very brilliant and transparent, may be worked
over in a way impossible by any ordinary method. A similar method is
described by Vibert" (Bazzi 1960, 108).

Artists' experiments with coating and glazing of paintings and
drawings with fish glue were recorded as early as the seventeenth
century. Fish glue produced by boiling of the swim bladders of
sturgeons was experimentally used by Van Dyck in his tempera
paintings. When fish glue was applied in many layers and in glazed
coats, the film formed was easily chipped off (Doerner 1984,
224-225).

These earlier attempts demonstrate that fish glue used alone
forms a brittle film. As with any other adhesive, when and where it
is appropriate to apply should be considered carefully. Perhaps the
brittleness of the film formed by this glue motivated artists to
introduce various plasticizers that are also used in conjunction
with fish glue in restoration. Molasses in England and honey in
Russia have often been used as natural plasticizers. For example,
isinglass glue mixed with honey had been used for the consolidation
of delaminated paint in Russian icons as early as the seventeenth
century (Petukhova 1993).

Drawings: Pastel Binder and Fixative

The makeup of soft pastels has not been changed much since the
fifteenth century when this medium came into existence. Pulverized
color pigments combined usually with white chalk were rolled
together into cylinders or other shapes with a small amount of
binder. Gum tragacanth and methyl cellulose are probably the most
favorable binders in modern manufacturing of soft pastels, although
in early recipes, milk, beer, ale, or fish glue had been employed
(Maheux 1988, 41).

Methods for fixing pastels have been a great concern for artists
working in this medium. Various techniques, from powdering the
surface of pastel with gum arabic and then fixing it with hot steam
and spraying it with a mixture of water, glue and spirit, to
spraying the verso of the pastel with skimmed milk, have been
implemented by artists in order to protect this fragile medium from
unavoidable deterioration. Milk, water, thin tempera, resin, spirit,
and also glue solutions have been the main components of many
recipes for pastel fixatives.

Among the artists seriously searching for a method to stabilize
the pastel medium and experimenting with isinglass glue, as a
component of fixatives are Latour and Degas. The following recipe
described by Loriot, and perhaps also used by Latour, includes
isinglass glue:

Melt about 150 grains of isinglass in about 3/4 pt. of pure water
in a double saucepan over a low fire. Strain through fine linen and
pour on to a plate while hot. Add 2 parts of wine spirit to 1 part
of glue. (Bazzi 1960, 98)

The method of fixing pastel with this solution, as Maria Bazzi
recommends, is by spraying the verso of artwork.

Besides its applications in graphic arts, fish glue material can
be found in priming, binding paint medium, glazing, and coating of
easel and encaustic paintings and icons. It proved to be an
excellent adhesive for wooden objects since the time of ancient
Egyptians, who knew the unique qualities of this material.

Conclusion

It is my belief that conservators have a responsibility to
preserve not only the physical structure of an object but also the
knowledge left to us by our fellow artists and restorers of an
earlier age. Those materials that well served artists and restorers
for centuries should not be forgotten. We might find them very
useful even today if we have a fresh look at their properties and
methods of application. In this article I hope to reawaken the
historic knowledge of the use of fish glue, one of the earliest
artist's materials, and to encourage its scientific research and its
use in conservation of historic and artistic works.

Acknowledgments

The author would like to thank the Samuel H. Kress Foundation for
supporting her research on fish glues, part of which is presented in
this article; Barbara Prior, reference librarian at the Fine Arts
Library of Cornell University, for her assistance in tracking down
earlier references; and Joan Ormondroyd for her advice, revision,
and encouragement.

Laurie, A. P. 1910. The materials of
the painter's craft in Europe and Egypt from earliest times to the
end of the XVII th. century, with some account on their preparation
and use. London & Edinburg: T. N. Foulis.

Petukhova, Tatyana. 1989. Potential
application of isinglass adhesive for paper conservation. The
Book and Paper Group Annual 8:58-61.

Siren, Osvald. 1936. The Chinese on the
art of painting. Beijing: Henri Vetch.

Sze, Mai-Mai. 1956. The way of Chinese
painting: its ideas and techniques with selections from the
seventeenth century mustard seed garden manual of painting.
New York: Vintage Books a Division of Random House.